Calpine's Calif. Delta unit in unplanned outage

LOS ANGELES, June 5 (Reuters) - Calpine Corp's (CPN.N: Quote, Profile, Research, Stock Buzz) 811-megawatt Delta natural gas-fired power station in California was fully off-line in an unplanned outage on Thursday after returning some of its production on Wednesday, the California Independent System Operator said in a report.

About 100 MW had returned to service, Cal ISO's report showed on Wednesday, after a planned outage that began April 27. But by Thursday afternoon the report showed an unplanned outage and increased the total out to the full plant output.

The station, which entered service in 2002, is located in Pittsburg, in Contra Costa County, about 40 miles (64 km) east of San Francisco. It is a combined-cycle plant with three combustion turbines, two 182 MW units and one 183 MW unit, and one steam turbine of 263 MW.

One MW powers about 700 homes in central and northern California. (Reporting by Bernard Woodall; Editing by Marguerita Choy)